CN116754991A - Multi-element leakage current measuring system - Google Patents

Abstract

The application discloses a multi-element leakage current measurement system. Wherein, this system includes: the device comprises a plurality of measuring stations, a measuring voltage source and a current measuring device, wherein each measuring station is used for placing an element to be measured, and the current measuring device for measuring the leakage current of the element to be measured is arranged in each measuring station; a measurement voltage source for providing a first measurement voltage for the component to be measured in the plurality of measurement stations; the current measuring device comprises a current limiting circuit, wherein the current limiting circuit is used for limiting the current value of the current to be measured flowing through the current measuring device not to exceed a preset current threshold value. The application solves the technical problem that the accuracy of the test result under the condition that the simultaneous test of multiple elements cannot be ensured due to the fact that the interference of the abnormal element to be tested on other elements to be tested cannot be isolated in the related technology.

Description

Multi-element leakage current measuring system

Technical Field

The application relates to the field of semiconductor testing, in particular to a multi-element leakage current measurement system.

Background

In the field of semiconductor testing, leakage current is an important test indicator. However, in the related art, under the condition of simultaneously measuring leakage currents of a plurality of elements, when a part of elements to be tested have abnormal testing, the related art cannot isolate interference of the abnormal elements to be tested on other elements, so that testing results of other testing elements are affected.

In view of the above problems, no effective solution has been proposed at present.

Disclosure of Invention

The embodiment of the application provides a multi-element leakage current measuring system, which at least solves the technical problem that the accuracy of a test result under the condition that the multi-element simultaneous test cannot be ensured due to the fact that interference of an abnormal element to be tested on other elements to be tested cannot be isolated in the related technology.

According to an aspect of an embodiment of the present application, there is provided a multi-element leakage current measurement system, including: the device comprises a plurality of measuring stations, a measuring voltage source and a current measuring device, wherein each measuring station is used for placing an element to be measured, and the current measuring device for measuring the leakage current of the element to be measured is arranged in each measuring station; a measurement voltage source for providing a first measurement voltage for the component to be measured in the plurality of measurement stations; the current measuring device comprises a current limiting circuit, wherein the current limiting circuit is used for limiting the current value of the current to be measured flowing through the current measuring device not to exceed a preset current threshold value.

Optionally, the high voltage ends of the components to be measured in the plurality of measuring stations are connected and the low voltage ends of the components to be measured are each connected to a current measuring device.

Optionally, the low voltage ends of the components to be measured in the plurality of measuring stations are connected, and the high voltage ends of the components to be measured are each connected to a current measuring device.

Optionally, the high voltage end of the element under test is connected to a current measuring device and the low voltage end of the element under test is connected to another current measuring device.

Optionally, the current measurement device further comprises an operational amplifier and a feedback resistor, wherein the current measurement device is connected in series into the measurement station through a first node and a second node, the first node is connected with the non-inverting input end of the operational amplifier, and the second node is connected with the inverting input end of the operational amplifier; the first end of the current limiting circuit is connected with the output end of the operational amplifier; the first end of the feedback resistor is connected with the second end of the current limiting circuit, the second end of the feedback resistor is connected with the second node of the operational amplifier, the voltage value of the connection point of the current limiting circuit and the feedback resistor is a second measurement voltage value corresponding to the element to be measured, and the current value of the current to be measured is determined according to the second measurement voltage value and the resistance value of the feedback resistor.

Optionally, the current measurement device further includes a protection resistor, wherein an inverting input terminal of the operational amplifier is connected to the protection resistor and is connected to the second node through the protection resistor, and the protection resistor is used for limiting a voltage value applied to the operational amplifier not to exceed a preset safety voltage threshold.

Optionally, the current measurement device further includes a high input impedance circuit, wherein an impedance value of the high input impedance circuit is greater than a preset impedance threshold, and the high input impedance circuit, the second end of the current limiting circuit and the first end of the feedback resistor are connected to the same connection point, so that the current to be measured flowing through the feedback resistor flows into the current limiting circuit, and a ratio of a current value of a current component of the current to be measured flowing into the current limiting circuit to a current value of the current to be measured is greater than a first preset ratio.

Optionally, the current limiting circuit includes a first transistor, a second transistor, a first resistor, a second resistor, and a current limiting voltage source, where the transistor type of the first transistor is a bipolar transistor, and the transistor type of the second transistor is a field effect transistor; the resistance of the first resistor is smaller than that of the second resistor, and the ratio of the resistance of the second resistor to that of the first resistor is not smaller than a second preset ratio; the resistance of the feedback resistor is smaller than that of the second resistor, and the ratio of the resistance of the second resistor to that of the feedback resistor is not smaller than a third preset ratio; an emitter of the first transistor is connected with a first end of the first resistor and a first end of the feedback resistor, a base electrode of the first transistor, a second end of the first resistor and a source electrode of the second transistor are connected to the same connecting point, a collector electrode of the first transistor, and a first end of the second resistor and a grid electrode of the second transistor are connected to the same connecting point; the second end of the second resistor is connected with a current-limiting voltage source; the drain electrode of the second transistor is connected with the output end of the operational amplifier.

Optionally, in the case that the current measurement is a measuring device for measuring a low-voltage side current of the element to be measured, a negative electrode of the current-limiting voltage source is connected with the second resistor, and a positive electrode of the current-limiting voltage source is grounded in a floating manner; in the case of a current measurement as a measuring device for measuring the high-side current of the element to be measured, the anode of the current-limiting voltage source is connected to the second resistor, and the cathode of the current-limiting voltage source is grounded.

Optionally, in a case where the current to be measured of the element to be measured is greater than a preset current threshold, the first transistor is in a conductive state, a voltage value between the gate and the source of the second transistor decreases, and a resistance value between the drain and the source of the second transistor increases.

In an embodiment of the present application, there is provided a multi-element leakage current measurement system including: the device comprises a plurality of measuring stations, a measuring voltage source and a current measuring device, wherein each measuring station is used for placing an element to be measured, and the current measuring device for measuring the leakage current of the element to be measured is arranged in each measuring station; a measurement voltage source for providing a first measurement voltage for the component to be measured in the plurality of measurement stations; the current measuring device comprises a current limiting circuit, wherein the current limiting circuit is used for limiting the current value of the current to be measured flowing through the current measuring device not to exceed a preset current threshold value, and the purpose of limiting the current of the element to be measured within an allowable range is achieved by adding the current limiting circuit in the current measuring device, so that the technical effect of avoiding the overlarge current of the element to be measured abnormally so as to interfere the test results of other elements is achieved, and the technical problem that the accuracy of the test results under the condition that the multi-element simultaneous test cannot be guaranteed due to the fact that the interference of the element to be measured abnormally to the other elements cannot be isolated in the related art is solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:

FIG. 1 is a schematic diagram of a device leakage current measurement circuit in the related art;

FIG. 2 is a schematic diagram of a multi-element leakage current measurement circuit according to the related art;

FIG. 3 is a schematic diagram of another multi-element leakage current measurement circuit in the related art;

FIG. 4 is a schematic diagram of a current limiting circuit in the related art;

FIG. 5 is a schematic diagram of a multi-element leakage current measurement system according to the present application;

FIG. 6 is a schematic diagram of another multi-element leakage current measurement system according to the present application;

FIG. 7 is a schematic diagram of a further multi-element leakage current measurement system according to the present application;

FIG. 8 is a schematic diagram of a further multi-element leakage current measurement system according to the present application;

FIG. 9 is a schematic view of a current measuring apparatus provided in accordance with the present application;

FIG. 10 is a schematic diagram of a current measuring device for measuring leakage current at a low voltage side of a device under test according to the present application;

FIG. 11 is a schematic diagram of a multi-component leakage current measurement system for measuring leakage current at a low voltage side of a device under test according to the present application;

fig. 12 is a schematic diagram of a current limiting circuit in a current measurement device according to the present application;

FIG. 13 is a schematic view of a current measuring device for measuring leakage current on a high voltage side of a device under test according to the present application;

fig. 14 is a schematic diagram of a connection mode between a device under test and a current measurement device when measuring a leakage current on a high voltage side of the device under test according to the present application.

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The leakage current of the element to be tested is a common test index in the field of semiconductor testing, and particularly in the technical field of discrete device testing, the leakage current of the element to be tested is an important component of direct current parameter testing. Taking a common Metal-Oxide-field effect transistor (MOSFET) as an example, common leakage current parameters include: zero gate voltage drain current, gate source leakage current, etc. In testing leakage currents, it is often necessary to apply a certain voltage or a certain set of voltages between several electrodes of the device under test, and then measure the current flowing through one or a certain set of electrodes, respectively, as shown in fig. 1. Factors to be considered in the test include test efficiency, test stability, test accuracy, safety, and the like.

Because only one device to be tested is measured at a time with low efficiency, the actual production requirement cannot be met, and in order to improve the production efficiency, a multi-station test mode for simultaneously testing a plurality of DUTs (Device Under Test, devices to be tested) is needed. In an ideal situation, in order to ensure a measurement result, a test loop, a test excitation source and a measurement instrument (an ammeter is indicated in a leakage current test) required by a test should be respectively configured for each of a plurality of devices under test, but in a multi-station high-voltage leakage current test, if a high-voltage power supply is configured for each station DUT, the cost of the ATE is greatly increased, and a plurality of high-voltage power supplies coexist, a large impact is brought to the whole system, the safety and stability of the whole system are affected, especially in a wafer test, the drains of all MOSFET devices on a wafer are shorted together in the current mainstream metal oxide field effect transistor MOSFET products, and if a high-voltage power supply is configured for each DUT, the parallel connection of a plurality of high-voltage power supplies is caused, so that serious crosstalk and safety problems are brought. Multi-station testing is therefore commonly performed in the related art using a multi-element measurement circuit as shown in fig. 2.

Fig. 2 is a multi-element measurement circuit for simultaneously measuring two devices under test. As can be seen from fig. 2, when measuring the multiple elements, the drains of the stations to be measured (the "D" pole in the figure) can be shorted together (actually, in wafer testing, the drains of all the devices to be measured are shorted together), the leakage current measurement modules are respectively placed at the sources of the stations to be measured (the "S" pole in the figure), and then the low ends of the leakage current measurement modules are shorted together. Thus, the same test excitation voltage is applied to a plurality of stations by one measurement voltage source (most high-voltage power sources), and the leakage current of each station is tested respectively.

Under the condition that each element to be measured is normal, the measuring circuit shown in fig. 2 is adopted, and the number of stations is increased according to the self requirement, so that the measurement of a plurality of elements to be measured can be realized. However, in the measurement circuit shown in fig. 2, when there is an abnormal device under test, other devices under test may be disturbed. For example, the first device under test is in a normal state, but the second device under test DS is abnormally short-circuited. At this time, when the voltage source is to apply a voltage with a voltage value equal to a preset voltage value, a problem of excessive current in the loop occurs. In addition, since in ATE, the voltage source generally has current monitoring and clamping functions, when the current in the loop exceeds the rated value, the voltage source actively reduces its output to protect the ATE equipment itself and the device under test. Therefore, when the abnormal current of the second element to be tested occurs, the excessive current flowing through the second element to be tested triggers a protection mechanism of the voltage source, so that the measured voltage source value is reduced, and the voltage excitation applied to the first element to be tested, which is originally normal, is far lower than the required value, so that the test is invalid.

In order to solve the above-described problems, the following two solutions are mainly adopted in the related art. The first solution is to monitor whether the voltage output by the voltage source reaches a set value before parallel testing is performed on a plurality of elements, and if the voltage does not reach the set value, consider that the element to be tested in a certain station exists in the current station to be tested as an abnormal element to be tested, and start to test the elements to be tested in each station in sequence, and test only one element to be tested at the same time. The method can seriously reduce the testing efficiency, and under the condition of low yield of the elements to be tested, the measuring efficiency by adopting the method is even lower than that of directly testing each element to be tested in sequence.

In another scheme, as shown in fig. 3, a current limiting circuit connected in series with the element to be tested and the ammeter is added in the station to be tested, and the current of the abnormal element to be tested is limited within an allowable range through the current limiting current. But the use of a current limiting circuit directly connected in series with the measurement circuit can result in the current limiting circuit being overly complex, as shown in fig. 4. And the current limiting circuit directly connected in series with the measuring circuit inevitably generates a voltage division effect on the tested device, so that the voltage actually applied to the tested device is lower than a set value, and the test result is inaccurate.

In order to solve this problem, related solutions are provided in the embodiments of the present application, and are described in detail below.

Fig. 5 is a diagram of a multi-element leakage current measurement system according to an embodiment of the present application, as shown in fig. 5, the system includes: a plurality of measuring stations 01, a measuring voltage source 02 and a current measuring device 03, wherein each measuring station 01 in the plurality of measuring stations 01 is used for placing an element to be measured, and each measuring station 01 is provided with the current measuring device 03 for measuring the leakage current of the element to be measured; a measurement voltage source 02 for providing a first measurement voltage for the components to be measured in the plurality of measurement stations 01; the current measuring device 03 comprises a current limiting circuit 04, wherein the current limiting circuit 04 is used for limiting the current value of the current to be measured flowing through the current measuring device 03 not to exceed a preset current threshold value.

In some embodiments of the present application, the connection relationship between each station in the multi-element leakage current measurement system provided in the embodiments of the present application is different due to different types of the devices to be measured. For example, for a plurality of devices under test that need to measure low-side leakage current, the connection relationship between each station in the multi-element leakage current measurement system is as shown in fig. 6, the high-voltage ends of the devices under test in a plurality of measurement stations 01 are connected, and the low-voltage ends of the devices under test are each connected to the current measurement device 03.

For a plurality of to-be-measured elements requiring measurement of high-side leakage current, the connection relationship between each station in the multi-element leakage current measurement system is shown in fig. 7, the low-voltage ends of the to-be-measured elements in the plurality of measurement stations 01 are connected, and the high-voltage ends of the to-be-measured elements are respectively connected to the current measurement device 03.

In the case that there are both the to-be-measured element that needs to measure the high-voltage side leakage current and the to-be-measured element that needs to measure the low-voltage side leakage current among the plurality of to-be-measured elements, the connection relationship of each station in the multi-element leakage current measurement system is shown in fig. 8, the high-voltage end of the to-be-measured element is connected to the current measurement device 03, and the low-voltage end of the to-be-measured element is connected to another current measurement device 03.

In the related art, a common current measuring device may be a voltage-dividing current measuring device or a feedback current measuring device. Fig. 9 is a schematic structural diagram of a current measuring part of the two current measuring devices, wherein the left side of fig. 9 is a voltage dividing type, and the right side of fig. 9 is a feedback type. In some embodiments of the application, in order to be able to integrate a current limiting circuit in the current measuring device and to ensure that the measurement result is not affected, a feedback current measuring device may be employed.

In some embodiments of the present application, as shown in fig. 10, the current measurement device 03 further includes an operational amplifier 05 and a feedback resistor 06. As can be seen from fig. 10, the current measuring device 03 is connected in series to the measuring station 01 via a first node, which is connected to the non-inverting input of the operational amplifier 05, and a second node, which is connected to the inverting input of the operational amplifier 05; the first end of the current limiting circuit 04 is connected with the output end of the operational amplifier 05; the first end of the feedback resistor 06 is connected with the second end of the current limiting circuit 04, the second end of the feedback resistor 06 is connected with the second node of the operational amplifier 05, the voltage value of the connection point of the current limiting circuit 04 and the feedback resistor 06 is a second measurement voltage value corresponding to the element to be measured, and the current value of the current to be measured is determined according to the second measurement voltage value and the resistance value of the feedback resistor 06.

A multi-element measurement system employing a current measurement device 03 as shown in fig. 10 is shown in fig. 11. Fig. 11 shows a multi-element leakage current measurement system for measuring leakage current on the low voltage side of two devices under test, and as can be seen from fig. 11, the current limiting circuit 04 is disposed in the current measurement device 03 instead of directly connected to the measurement system and connected in series with the devices under test, so that the problem of inaccurate measurement result caused by voltage division of the current limiting circuit 04 can be avoided.

As an alternative embodiment, as shown in fig. 12, the current measuring device 03 further includes a protection resistor 07, wherein an inverting input terminal of the operational amplifier 05 is connected to the protection resistor 07 and is connected to the second node through the protection resistor 07, and wherein the protection resistor 07 is used to limit a voltage value applied to the operational amplifier 05 from exceeding a preset safety voltage threshold.

In some embodiments of the present application, as shown in fig. 12, the current measurement device 03 further includes a high input impedance circuit 13, where an impedance value of the high input impedance circuit 13 is greater than a preset impedance threshold, and the high input impedance circuit 13, a second end of the current limiting circuit 04 and a first end of the feedback resistor 06 are connected to the same connection point, so that a current to be measured flowing through the feedback resistor 06 flows into the current limiting circuit 04, and a ratio of a current value of a current component of the current to be measured flowing into the current limiting circuit 04 to a current value of the current to be measured is greater than a first preset ratio. The first preset ratio can be set by the user according to actual needs.

The high input impedance circuit 13 may be a follower circuit or the like for avoiding generation of a bypass circuit or limiting the current magnitude of the bypass current within an allowable range, so that it can be considered that the current to be measured flowing through the original to be measured flows into the current limiting circuit 04 via the feedback resistor 06 in the actual measurement process. When faults such as abnormal short circuit occur, the current limiting circuit 04 starts to work, and the current to be measured of the element to be measured in an abnormal state is limited within an allowable range, so that normal testing of a normal station is ensured.

As an alternative embodiment, as shown in fig. 12, the current limiting circuit 04 includes a first transistor 08, a second transistor 09, a first resistor 10, a second resistor 11, and a current limiting voltage source 12, where the transistor type of the first transistor 08 is a bipolar transistor, and the transistor type of the second transistor 09 is a field effect transistor; the resistance of the first resistor 10 is smaller than that of the second resistor 11, and the ratio of the resistance of the second resistor 11 to the resistance of the first resistor 10 is not smaller than a second preset ratio; the resistance value of the feedback resistor 06 is smaller than that of the second resistor 11, and the ratio of the resistance value of the second resistor 11 to the resistance value of the feedback resistor 06 is not smaller than a third preset ratio; an emitter of the first transistor 08 is connected to a first end of the first resistor 10 and a first end of the feedback resistor 06, a base of the first transistor 08, a second end of the first resistor 10 and a source of the second transistor 09 are connected to the same connection point, a collector of the first transistor 08, and a first end of the second resistor 11 and a gate of the second transistor 09 are connected to the same connection point; a second end of the second resistor 11 is connected with a current-limiting voltage source 12; the drain of the second transistor 09 is connected to the output of the operational amplifier 05. The second preset ratio can be set by the user according to the actual needs.

In addition, as can be seen from fig. 12, in the case where the current measurement is a measuring device for measuring the low-side current of the element to be measured, the negative electrode of the current-limiting voltage source 12 is connected to the second resistor 11, and the positive electrode of the current-limiting voltage source 12 is grounded to float.

Specifically, the field effect transistor in fig. 12 may be a metal oxide field effect transistor, a SiC field effect transistor, or a GaN field effect transistor. As can be seen from the view of figure 12,since the high input impedance circuit 13 is added in the current measuring device 03, the current signal to be measured (i.e., the current to be measured flowing through the feedback resistor 06) flows entirely through the first resistor 10, and a voltage V is generated across the first resistor 10 _R1 . During normal test, the current flowing through the feedback resistor 06 is smaller, V _R1 The GS voltage of the second transistor 09 is determined entirely by the current limiting voltage source 12, which is insufficient to turn on the first transistor 08. The output voltage value of the current-limiting voltage source 12 is generally above 10V, so that the second transistor 09 is in a complete on state, and thus, the on resistance of the second transistor 09 and the resistance of the first resistor 10 are far smaller than the resistance of the feedback resistor 06, so that the current-limiting circuit 04 will not affect the test under normal conditions.

When the element to be tested fails, such as abnormal short circuit, the current flowing through the feedback resistor 06 increases, V _R1 And then increases until the forward turn-on voltage of the PN junction between the BE two poles of the first transistor 08 is exceeded, thereby turning on the first transistor 08. The second resistor 11 with a larger resistance is selected so that after the first transistor 08 is turned on, the GS voltage value of the second transistor 09 mainly depends on the CE voltage drop of the first transistor 08, so that the voltage Vgs between the G pole and the S pole of the second transistor 09 decreases sharply with the increase of the current flowing through the feedback resistor 06, thereby increasing the resistance between the DS of the second transistor 09 sharply until the magnitude of the current flowing through the feedback resistor 06 is limited within a preset range.

As an alternative embodiment, in a case where the current to be measured of the element to be measured is greater than the preset current threshold, the first transistor 08 is in an on state, the voltage value between the gate and the source of the second transistor 09 decreases, and the resistance value between the drain and the source of the second transistor 09 increases.

In some embodiments of the present application, there is also provided a current measuring device 03 for measuring a current on a high voltage side of an element to be measured as shown in fig. 13. As can be seen from fig. 13, in the case of a current measurement as a measuring device for measuring the high-side current of the element to be measured, the positive pole of the current-limiting voltage source 12 is connected to the second resistor 11, and the negative pole of the current-limiting voltage source 12 is grounded. When the high-side leakage current of the device under test is tested, the connection relationship between the device under test and the current measuring device 03 is shown in fig. 14.

The application provides a multi-element leakage current measurement system, which comprises a plurality of measurement stations 01, a measurement voltage source 02 and a current measurement device 03, wherein each measurement station 01 in the plurality of measurement stations 01 is used for placing a component to be measured, and each measurement station 01 is provided with the current measurement device 03 for measuring the leakage current of the component to be measured; a measurement voltage source 02 for providing a first measurement voltage for the components to be measured in the plurality of measurement stations 01; the current measurement device 03 comprises a current limiting circuit 04, wherein the current limiting circuit 04 is used for limiting the current value of the current to be measured flowing through the current measurement device 03 not to exceed a preset current threshold value, and the current limiting circuit 04 is added in the current measurement device 03, so that the purpose of limiting the current of the element to be measured within an allowable range is achieved, the technical effect of avoiding the overlarge current of the abnormal element to be measured so as to interfere with the test results of other elements is achieved, and the technical problem of the accuracy of the test results under the condition that the multi-element simultaneous test cannot be guaranteed due to the fact that the interference of the abnormal element to be measured to the other elements cannot be isolated in the related art is solved.

The multi-element leakage current measuring system provided by the application can measure a plurality of elements at the same time, so that the testing efficiency is higher. In addition, the current limiting circuit 04 is arranged in the current measuring device 03, so that the current limiting function during abnormal short circuit can be realized, the normal station test can not be influenced, and the test efficiency during parallel test of a plurality of elements to be tested is further improved.

In addition, the current limiting circuit 04 is arranged in the current measuring module, so that the system provided by the application has no influence on stations for normal testing, including the influence on testing efficiency, testing waveform, testing voltage precision and the like, and therefore, compared with a mode of directly connecting the current limiting circuit 04 with an original to be tested in series, the system provided by the application has the advantage that the testing precision is improved.

Besides improving the test precision, the design difficulty of the current limiting circuit 04 can be greatly reduced by adopting the mode of arranging the current limiting circuit 04 in the current measuring device 03. Because the current limiting circuit 04 in the leakage measurement module basically has no influence on normal measurement, the current limiting circuit 04 which can withstand the Vds voltage (the voltage between the D electrode and the S electrode of the element to be measured) is selected, so that the current limiting circuit has no many limitations in the prior art, and the design difficulty is greatly reduced.

It should be noted that the multi-element leakage current measurement system provided by the application can be easily applied to high-voltage measurement scenes of several kilovolts. Taking the above embodiment as an example, only the second transistor needs to be replaced by a transistor with voltage resistance meeting the preset requirement, and the circuit can be applied to the high-voltage measurement scene without adjusting the circuit. For example, the leakage measuring unit can be applied to an Idss test of 6 kilovolts by replacing the second transistor with an IGBT of more than 6 kilovolts, so that 6 kilovolts Idss multi-station high-speed parallel measurement is realized. That is, the multi-element leakage current measurement system provided by the application can realize normal operation under various application scenes by replacing each component with an equivalent functional component with different parameters and different performances under the condition of not changing the connection relation of each component in the system.

The foregoing embodiment numbers of the present application are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments.

In the foregoing embodiments of the present application, the descriptions of the embodiments are emphasized, and for a portion of this disclosure that is not described in detail in this embodiment, reference is made to the related descriptions of other embodiments.

In the several embodiments provided in the present application, it should be understood that the disclosed technology may be implemented in other manners. The above-described embodiments of the apparatus are merely exemplary, and the division of the units, for example, may be a logic function division, and may be implemented in another manner, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interfaces, units or modules, or may be in electrical or other forms.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the related art or all or part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a removable hard disk, a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely a preferred embodiment of the present application and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present application, which are intended to be comprehended within the scope of the present application.

Claims (10)

1. A multi-element leakage current measuring system is characterized by comprising a plurality of measuring stations, a measuring voltage source and a current measuring device, wherein,

each measuring station of the plurality of measuring stations is used for placing an element to be measured, and each measuring station is provided with the current measuring device for measuring the leakage current of the element to be measured;

the measuring voltage source is used for providing a first measuring voltage for the element to be measured in the measuring stations;

the current measuring device comprises a current limiting circuit, wherein the current limiting circuit is used for limiting the current value of the current to be measured flowing through the current measuring device not to exceed a preset current threshold value.

2. The multi-element leakage current measurement system of claim 1, wherein the high voltage ends of the devices under test in the plurality of measurement stations are connected and the low voltage ends of the devices under test are each connected to the current measurement device.

3. The multi-element leakage current measurement system of claim 1, wherein the low voltage ends of the devices under test in the plurality of measurement stations are connected and the high voltage ends of the devices under test are each connected to the current measurement device.

4. The multi-element leakage current measurement system of claim 1, wherein a high voltage end of the device under test is connected to the current measurement device and a low voltage end of the device under test is connected to another of the current measurement devices.

5. The multi-element leakage current measurement system according to any one of claims 1-4, wherein the current measurement device further comprises an operational amplifier and a feedback resistor, wherein,

the current measuring device is connected in series into the measuring station through a first node and a second node, wherein the first node is connected with the non-inverting input end of the operational amplifier, and the second node is connected with the inverting input end of the operational amplifier;

the first end of the current limiting circuit is connected with the output end of the operational amplifier;

the first end of the feedback resistor is connected with the second end of the current limiting circuit, the second end of the feedback resistor is connected with the second node of the operational amplifier, the voltage value of the connection point of the current limiting circuit and the feedback resistor is a second measurement voltage value corresponding to the element to be measured, and the current value of the current to be measured is determined according to the second measurement voltage value and the resistance value of the feedback resistor.

6. The multi-element leakage current measurement system according to claim 5, further comprising a protection resistor in the current measurement device, wherein,

the inverting input end of the operational amplifier is connected with the protection resistor and is connected with the second node through the protection resistor, wherein the protection resistor is used for limiting the voltage value applied to the operational amplifier not to exceed a preset safety voltage threshold value.

7. The multi-element leakage current measurement system of claim 5, further comprising a high input impedance circuit in the current measurement device, wherein,

the impedance value of the high input impedance circuit is larger than a preset impedance threshold value, the second end of the current limiting circuit and the first end of the feedback resistor are connected to the same connecting point, the high input impedance circuit is used for enabling the current to be measured flowing through the feedback resistor to flow into the current limiting circuit, and the ratio of the current value of the current component of the current flowing into the current limiting circuit to the current value of the current to be measured is larger than a first preset ratio.

8. The multi-element leakage current measurement system of claim 5, wherein the current limiting circuit comprises a first transistor, a second transistor, a first resistor, a second resistor, a current limiting voltage source, wherein,

the transistor type of the first transistor is a bipolar transistor, and the transistor type of the second transistor is a field effect transistor;

the resistance of the first resistor is smaller than that of the second resistor, and the ratio of the resistance of the second resistor to that of the first resistor is not smaller than a second preset ratio;

the resistance of the feedback resistor is smaller than that of the second resistor, and the ratio of the resistance of the second resistor to the resistance of the feedback resistor is not smaller than a third preset ratio;

the emitter of the first transistor is connected with the first end of the first resistor and the first end of the feedback resistor, the base electrode of the first transistor, the second end of the first resistor and the source electrode of the second transistor are connected to the same connecting point, the collector electrode of the first transistor, and the first end of the second resistor and the grid electrode of the second transistor are connected to the same connecting point;

the second end of the second resistor is connected with the current-limiting voltage source;

the drain electrode of the second transistor is connected with the output end of the operational amplifier.

9. The multi-element leakage current measurement system of claim 8, wherein,

when the current measurement is a measurement device for measuring the low-voltage side current of the element to be measured, the negative electrode of the current-limiting voltage source is connected with the second resistor, and the positive electrode of the current-limiting voltage source is grounded in a floating manner;

and under the condition that the current measurement is a measurement device for measuring the high-voltage side current of the element to be measured, the anode of the current-limiting voltage source is connected with the second resistor, and the cathode of the current-limiting voltage source is grounded in a floating mode.

10. The multi-element leakage current measurement system of claim 8, wherein the first transistor is in an on state, a voltage value between a gate and a source of the second transistor decreases, and a resistance value between a drain and a source of the second transistor increases when the current to be measured of the element to be measured is greater than the preset current threshold.